Loud speaker unit and drive mechanism therefor



Oct. 20, 1931. J. R. B-ARNHART LOUD SPEAKER UNIT AND DRIVE MECHANISM THEREFOR Filed Nov. 28, 1928 Patented Get. 20, 1931 UNlTED STATES PATENT OFFICE JOB R. BARN'HART, OF LAKEWOOD, OHIO, ASSIGNOR TO THE STERLING MANUFACTUR- ING- COMPANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO IOUD SPEAKER UNIT AND DRIVE MECHANISM THEREFOR Application filed November 28, 1928. Serial No. 322,335.

This invention relates generally to a loud speaker unit and more particularly to a speaker unit which is especially adapted for use in connection with radio receiving sets.

One of the main objects of the invention is to provide a simple, efiicient and compact speaker unit which is provided with a very eiiicient drive or mechanism for transmitting the movement of the armature to the in diaphragm of the speaker without materially diminishing the effective force of the armature vibration.

Another object of the invention is to provide a loud speaker unit in which the magnet and armature are disposed at right angles to the axis of the diaphragm of the speaker so as to conserve space and to provice a rigid and compact unit which is provided with a leverage system including a bell crank for transmitting vibrations of the armature to the diaphragm without appreciably diminishing. these vibrations or impulses.

Another object of the invention is to provide a drive between the armature and diaphragm of a loud speaker unit which will, by reason of its design and construction, save considerable space in the depth of the housing and at the same time prevent side vibration of the diaphragm.

A still further object of the invention is to provide a driving connection between the armature and diaphragm of a loud speaker unit which consists essentially of a lever so arranged and designed as to eliminate the usual losses and false vibrations at the point of transmission and which is so mounted, reinforced and constructed that it will have a movement only in a single plane substantially parallel to the axis of the diaphragm.

Further and more limited objects of the invention will appear as the description proceeds and by reference to the accompanying drawings in which Fig. 1 is a vertical sectional view of a loud speaker unit embody- 45 ing my invention and disclosing the essential features thereof; 2 is a fragmentary view in rear elevation and disclosing the relative location of the several elements; Fig. 3 is a vertical sectional view. disclosing the design in details of construction of the mechanism for transmitting the movement of the armature to the diaphragm; and Fig. l is a horizontal sectional view on the line H of Fig. 3.

Referring now to the drawings the reference character 1 designates a suitable frame which is preferably frusto-conical in shape and in which is arranged a diaphragm 2 of a shape well known to those skilled in the art. Secured to the rear portion of the frame 1 is a plate 3 which is held in place by suitable bolts 4, 5 and 6 and nuts 7, 8 and 9. Mounted on the plate 3 is a magnet 10 of the horseshoe type which is held in place by bolts 11 and 12 and a plate or strap 13 which fits over the screw 5 and bears against the top of the magnet and is held in place bythe nut 8. Disposed ad'- jacent the opposite ends of the magnet 10 are a pair of pole pieces 14 and 15 which are securely placed by means of a plate 16 and by the screws 11 and 12. Carried by the plate 16 are a pair of coils 19 (only one of which is shown in the drawings) in which is arranged the armature 20 in a manner well known to those skilled in the art.

Connected with the diaphragm 2 in any suitable manner is a pin 21 which is connected with the armature 20 in a manner to be hereinafter described. Carried by the plate 16 and secured thereto by screws 22, 23 is a plate 24 of nonconducting material having terminals 25 and 26 to which the opposite ends of the coils 19 are connected respectively and to which are connected the conductors leading from the receiving set. It will therefore be seen that the armature 20 will be vibrated in accordance with and responsive to the current flowing in the set. It will also be seen that the armature 20 vibrates in a plane at right angles to the axis of the pin 21 and diaphragm 2. In order to transmit the vibrations or impulses of the armature 20 to the diaphragm pin 21, I provide a mechanism which consists essentially of a lever 27, the details of which are shown most clearly in Figs. 3 and 41-. The lever 27 comprises portions 28, 29 and 30. The portion 28 is a substantially straight piece of metal and is secured to the plate 3 by meansof a screw 18. The portions 29 and 80 preferably consists of a single piece of metal bent into the shape shown in Fig. 3. The portion 30 has an opening 36 therein through which extends the arm of portion 28. The upper end of the arm 28 is rigidly connected with the upper end of the portion 29 and the end of the arm 30 is rigidly connected with the plate 3 by means of a screw 17. The opening 36 is of sufficient size to allow considerable movement of the arms 28 and 30 with respect to each other without contacting. The adjacent edges of the plate 3 are preferably disposed at right angles to each other. The arms 28, 29 and 30 are preferably embossed inwardly, as shown, so as to render the same more rigid. The pin 21 is projected through suitable openings provided in the upper end of the member 27 and is preferably soldered thereto as shown at 32. The armature 20 is connected with the member 27 by means of a pin which has one end rigidly connected with the armature and its opposite end projected through suitable openings provided in the member 27 and soldered thereto as shown at 34;.

Secured to and surrounding the arm 29 is a dam ening device 35, preferably of rubber, and w ich serves to prevent excessive vibration.

It will therefor be seen that the arms 28, 29 and 30 arranged and connected as described provide a lever which is substantially the shape of the figure 4, the opposite ends of the lever being supported in different planes substantially at right angles to each other. With the parts arranged and supported as shown and described, it will be seen that the lever will have a movement only in a single plane atright angles to the plane of movement of the armature. The vibrations or impulses of the armature will be transmitted to the dia hragm pin 21 without appreciably diminishing the same. The size and shape of the lever 27 may be varied as desired without departing from the spirit of my invention and the embodiment of my invention disclosed is merely illllstrative and not to be considered in a limiting sense. Various other changes may be made in the shape, size and arrangement of parts without departing from the spirit of my invention and it should be understood that my invention is limited only in accordance with the scope of the appended claims.

It will now be clear that I have provided a loud speaker unit having a driving connection between the armature and the diaphragm which will transmit the vibrations of the armature to the diaphragm without appreciably diminishing these vibrations or impulses and which at the same time will eliminate the usual losses and false vibrations at the point or'ftransmission.

It will now be clear that I have provided a loud speaker unit which will accomplish the objects of the invention as hereinbefore stated.

Having thus described my invention, What I claim is:

1. In a radio loud speaker unit, the combination of an armature, a conical diaphragm disposed with its axis at right angles to the plane of vibration of said armature, of means for transmitting the vibrations of said armature to said diaphragm without materially diminishing the effective force of said vibrations, said means comprising a triangularly bent strip connected with said diaphragm and armature atthe two corners intermediate its ends and resiliently supported for pivotal movement at the other corner so as to oscillate only in a single plane.

2. In a radio loud speaker unit, the combination of an armature, a diaphragm disposed with its axis at an angle to the plane of vibration of said armature, of means for transmitting the vibrations of said armature to said diaphragm without materially diminishing the effective force of said vibrations, said means comprising a bent resilient strip triangular in shape and connected intermediate its ends with said armature and diaphragm, the opposite ends of said strip being supported in two planes at right angles to each other, whereby to secure substantially a pivotal action.

3. In a radio loud speaker unit, the combination of a frame, a diaphragm carried by said frame, a pin connected with said diaphragm and projecting rearwardly therefrom, a magnet carried by said frame, a coil disposed within said magnet, an armature arranged within said coil and disposed to vibrate at an angle to the axis of said pin, means for transmitting the vibrations of said armature to said diaphragm without materially diminishing the efi'ective force of said vibrations, said means comprising a resilient strip bent into the form of a triangle and atthe corners intermediate its ends connected with said diaphragm pin and said armature, portions of said triangular member being embossed to add rigidity thereto, said strip being so mounted as to have movement only in a single plane.

4. A loud speaker including a diaphragm, a vibratory armature, and means for transmitting the vibrations of said armature to said diaphragm, said means including, a mounting block, resilient strips attached to adjacent faces of said block adjacent the same corner, a third strip connecting ends of said strips, and means connecting the ends of said third strip to said diaphragm and said armature respectively.

5. A loud speaker including a diaphragm, a vibratory armature, and means for transmitting the vibrations of said armature to said diaphragm, said means including, a mounting block, resilient strips attached to adjacent faces of said block, a third strip connecting ends of said strips, and means connecting the ends of said third strip to said diaphragm and said armature respectively, said resilient strips crossing each other at the junction of said adjacent faces.

6. A loud speaker including a diaphragm, a vibratory armature, and means for trans mitting the vibrations of said armature to said diaphragm, said means including, a mounting block, resilient strips attached to adjacent faces of said block, a third strip connecting ends of said strips, and means connecting the ends of said third strip to said diaphragm and said armature respectively, one of said resilient strips having a slot therein and the other said strip passing through said slot. 7

In testimony whereof, I hereunto afiix my signature.

JOB R. BARNHART. 

